BRPI0807657A2 - MULTIPLE COOKED OVEN - Google Patents

Abstract

A multiple hearth furnace including a rabble arm with a tubular structure and a solid plug body. The latter is received in a socket arranged in an arm fixing node. It has an axial through boring and cooling fluid supply and return channels arranged around this through boring. A clamping bolt is rotatably fitted in the through boring. It has a bolt head, which can be brought by rotation into and out of hooking engagement with an abutment surface on the arm fixing node. A threaded end of the clamping bolt sticks out of the through boring at the rear end of the plug body. A threaded sleeve, which is screwed onto this threaded end, bears on an abutment surface at the rear end of the plug body for exerting a clamping force onto the clamping bolt.

Description

DESCRIPTIVE REPORT Invention Patent Application for “MULTIPLE COOKED OVEN”

Technical field

The present invention relates generally to an oven

with multiple crucible (FCM).

State of the art

We have been with multiple crucible (FCM) have been used for about a century to heat or roast many types of 10 materials. They comprise a plurality of crucible chambers arranged one above the other. Each of these crucible chambers comprises a circular crucible which alternatively has a central material drop hole or a plurality of peripheral material drop holes. A vertical rotary axis extends centrally through all of these overlapping crucible chambers and each has a revolving arm clamping joint. The revolving arms are connected with one end attached to such arm clamping joint (typically there are two to four revolving arms per crucible chamber). Each revolving arm comprises a plurality of revolving teeth 20 extending downwardly into the material on the crucible. When the vertical rotary shaft is rotated, the revolving arms sweep the material over the crucible with their revolving teeth toward the central drop hole or toward the peripheral fall holes in the crucible. Thus, material discharged into the highest crucible chamber is slowly moved downward through all successive crucible chambers and is pushed by the rotating revolving arms over successive crucibles alternately from the periphery to the center (in a crucible with a central material drop hole) and from the center to the periphery (in a crucible with a peripheral material drop hole). Arriving at the lower crucible chamber, the roasting or hot material leaves the FCM through an oven discharge opening.

In an FCM, the vertical rotary shaft as well as the arms

Revolvers are tubular structures that are cooled by a refrigerant, usually a gaseous refrigerant such as ambient air (for simplicity, the gaseous refrigerant will be referred to here as a “refrigerant” even though it is a mixture of several gases). The vertical rotary shaft 10 includes a refrigerant distribution channel for supplying refrigerant to the revolving arms. From this refrigerant distribution channel, refrigerant is channeled through the connection between the revolving arm and the revolving arm retaining gasket into the revolving arm tubular structure. Since the revolving arm cooling system is normally a closed system, the refrigerant gas that returns from the revolving arm must be channeled through the connection between the revolving arm and the revolving arm retaining gasket into a discharge channel. of gases on the vertical rotary axis.

The connection between the end of the revolving arm attached to the vertical rotary shaft must meet at least the following requirements. It must be strong enough to withstand not only the weight of the arm but also the considerable torque and shear stresses when the revolving teeth roll the material over the crucible. It must be safe at FCM operating temperatures, ie temperatures up to 1,000 ° C, and when the revolving arm is subject to vibration. It shall be able to channel refrigerant from the vertical rotary shaft to the revolving arm and vice versa, with a reasonable pressure drop and no refrigerant leak into a crucible chamber and between the supply flow and the return flow of the refrigerant gas. Last but not least, it should allow for easy replacement of the revolving arm, preferably without having to completely cool the FCM.

In the last hundred years, many different connections have been described between the cantilever-supported revolving arm and the vertical rotary shaft. For example:

US 1,164,130 and US 1,468,216 describe an FCM in which the revolving arm is provided with a tubular coupling end that fits into an inlet provided on the vertical rotary shaft. The tubular coupling end of the revolving arm is basically a cylindrical body but can be slightly tapered. To secure the revolving arm in its proper position, its tubular coupling end is provided with a locking trigger adapted to pass through a slot provided in a rim at the entrance to the housing and to engage an inclined inner edge of a shoulder. locking or cam surface provided on the inside wall of the housing. The tubular coupling end of the revolving arm is inserted into the housing and then rotated 90 ° to engage the locking trigger through the locking shoulder and bring the tubular coupling end of the revolving arm into the housing. A locking shoulder is provided over the inner wall of the housing to prevent further pivoting movement of the revolving arm when the parts have been placed in proper positioning. Such prior art locking system can easily loosen during FCM operation. Also, turning the revolving arm 90 ° to secure it in the housing is not an easy operation inside a crucible chamber.

FR 620.316 describes an FCM in which the revolving arm is provided with a tubular cylindrical coupling end that fits within a cylindrical inlet provided in a vertical rotary axis revolving arm clamping joint. A crooked rim extends over the full length of the revolving arm through one of two overlapping channels in the revolving arm. The end of the bent ring that protrudes eccentrically out of the tubular cylindrical coupling end of the revolving arms supports a dovetail-shaped mallet-shaped head to fit into a dovetail-shaped notch. on an inner wall of the revolving arm clamping joint. The end of the rim projects axially outwardly from the front end of the revolving arm and supports a thread on which a nut is tightened. Tightening this nut axially presses the tubular cylindrical coupling end of the arm into its

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cylindrical inlet on the revolving arm fixing joint. Of course, it would not be very easy to fit the dovetail head of the rim into the dovetail notch in the revolving arm clamping joint.

US 1,687,935 describes an FCM wherein the revolving arm is provided with a tubular conical coupling end that fits an adapter member over the shaft. The tubular conical coupling end has two convex cylindrical support portions 20 spaced thereon. The smallest convex cylindrical support portion located at the front end of the tubular conical coupling end fits into a conduit cylindrical coupling sleeve within the adapter member. The largest convex cylindrical support portion located at the rear end of the tubular conical coupling end 25 fits into a cylindrical coupling sleeve at the adapter member inlet. A radial locking pin is used to secure the tubular tapered coupling end of the revolving arm within the adapter member. Such a revolving arm locking system can easily loosen when the revolving arm is subjected to vibrations. Moreover, one can easily imagine that it would not be easy to assemble or disassemble the safety pin without entering the FCM. Last but not least, the adapter member described in US 1,687,935 is probably too bulky to be integrated into a full-size vertical rotary axis.

US 3,419,254 describes an FCM in which the fastening system for cantilever revolving arms is similar to the system described in US 1,687,935. The revolving arm is provided with a tubular tapered coupling end that fits into an opening in the shaft. The tubular conical coupling end has two convex cylindrical support portions spaced thereon. The smallest convex cylindrical support portion located at the front end of the tubular tapered coupling end fits into an opening in an inner tubular member of the vertical rotary shaft. The largest convex cylindrical support portion at the rear end of the tubular tapered coupling end fits into a cylindrical coupling surface that surrounds an opening within an outer tubular member of the shaft. A radial locking pin is used to secure the tubular tapered coupling of the revolving arm within the shaft. Such a revolving arm locking system can easily loosen when the revolving arm is subjected to vibrations. In addition, one can easily imagine that it will not be easy to assemble or disassemble the safety pin without entering the FCM. Last but not least, the integration of the cylindrical support openings for the tubular conical coupling end 25 into the inner and outer tubular members of the vertical rotary shaft requires considerable local reinforcement of these inner and outer tubular members and also causes problems with regards gas leakage.

US 1,732,844 describes an FCM in which the revolving arm is provided with a tubular coupling end that fits into an inlet provided on a large diameter vertical rotary shaft. A concave conical seating surface is disposed about the inlet inlet opening and a convex conical counter-seating surface formed by a protrusion on the tubular coupling end of the revolving arm. The tubular coupling end is secured at its entrance by a latch that can be operated from within the shaft and fits into a protrusion formed at the tubular coupling end of the revolving arm. It is evident that such a revolver connection system is only possible for an FCM having a large diameter vertical rotary shaft 10, to allow the fixing of the revolving arms from within the vertical rotary shaft.

DE 350646 describes an FCM that is designed for use with air and water as a refrigerant. The revolving arm is provided with a tubular coupling end that fits within a connector housing of a large diameter vertical rotary shaft. The connector housing comprises an inlet opening surrounded by a first concave conical seating surface and an inner partition wall with a second opening. The inlet opening gives access to a first connecting chamber and the opening in the inner partition wall gives access to a second connecting chamber, which is separated from the first connecting chamber by the inner partition wall. The tubular coupling end of the revolving arm has a protrusion that forms a convex conical back seat surface seated on the first concave conical seat surface 25 surrounding the inlet opening of the connector box. A tapered extension of the tubular coupling extends sealingly through the second opening into the second connecting chamber. The tapered extension of the tubular coupling supports a threaded rod that seals inwardly into the shaft where it is fixed by means of a nut. Of course, such a revolving connector system is only possible for an FCM having a large diameter rotary axis to be integrated with a very large connector housing and to allow the revolving arms to be fixed from within the vertical rotary axis.

DE 263939 describes a revolving arm attached to a hollow shaft

Vertical rotary. The revolving arm includes a tubular cast iron frame that is designed for a refrigerant to circulate through it. A cylindrical tubular coupling end of the revolving arm is received in a cylindrical inlet disposed on the vertical rotary hollow shaft. A protruding surface of this coupling end rests on a seating surface that surrounds the inlet on the vertical axis. A sealing ring is disposed between the projecting surface of the coupling end and the seating surface on the vertical axis. A setscrew, which extends from the coupling end of the revolving arm 15 to the front end of the revolving arm, is provided to secure the revolving arm with its coupling end to the inlet. This locking screw protrudes out of the coupling end of the revolving arm, where it has a screw head that can be engaged and detached by rotating the locking screw about 20 its center axis to a bearing surface on the locking joint. arm At the front end of the revolving arm, a threaded cover is screwed over a screwed end of the clamping screw to exert a clamping force on the clamping screw. In an alternative solution, the bolt head is designed as a threaded nut 25. It should be noted that the revolving arm fastening means described in DE 263939 has major disadvantages. A slight mechanical deformation or overheating of the revolving arm can even deform, damage or even break the retaining screw extending through the revolving arm. In particular, it should be noted that even small plastic expansion of the clamping screw due to, for example, overheating of the revolving arm would reduce the clamping force to zero. Last but not least, it would be very difficult to disassemble a revolving arm once its retaining screw was only slightly deformed.

DE 268602 describes a tubular revolving arm which is said to overcome the disadvantages of the revolving arm disclosed in DE 263939. The revolving arm with its cylindrical coupling end forms a one-piece cast pipe with a central partition wall. This separates a first refrigerant gas passage flowing to the front end of the revolving arm from a second refrigerant gas passage flowing back to the coupling end. A short-length setscrew is disposed in a tubular housing that projects axially into the tubular coupling end. A first end of the setscrew extends out of the coupling end of the revolving arm, where it has a set screw head which can be rotated by the setscrew around its central axis in a snap-in and off position. a bearing surface on the arm clamping joint. A threaded bushing is screwed onto a threaded end of the set screw that protrudes out of the tubular housing. This threaded bushing rests on the extreme face of the tubular housing to exert a clamping force on the clamping screw. The middle portion of the partition wall is bent over its entire length to provide free access to the threaded bushing from the front end of the revolving arm; so that the threaded bushing can be tightened or loosened with a wrench mounted on a bar. The refrigerant supply means comprises an opening which is disposed in the cylindrical wall of the tubular extension to communicate with said first passage. The refrigerant return means comprises an opening, which is arranged in a plate at the bottom of the tubular extension to communicate with said second passage.

In modern FCMs, the revolving arm comprises more

often a connector branch with an annular flange to connect a revolving arm to it. The revolving arm comprises at its rear end a tubular coupling body with an annular counterflange which is screwed into the annular flange of the connector branch. Such a flange connection ensures high mechanical strength even at high operating temperatures of the FCM and hardly loosens when the revolving arm is subjected to vibrations. However, exchanging a revolving arm with a flange connection requires the exchange workers to enter the crucible chamber to separate or renew the flange connection between the revolving arm and the connector branch. This clearly requires the FCM to be cooled before changing the revolving arm.

Technical problem

A first object of the present invention is to provide an FCM with a compact system for connecting the revolving arms to the vertical rotary axis, ensuring that the revolving arms are securely attached to the rotary axis but still easily interchangeable, and in which the revolving arm securing means are relatively well protected against mechanical deformation and overheating of the revolving arm.

General Description of the Invention

The present invention proposes an FCM comprising a vertical rotary hollow shaft with at least one revolving arm. This at least one revolver includes a tubular structure for circulating refrigerant through it and a coupling end that is received at an inlet arranged in a vertical rotary hollow shaft arm retaining joint. This coupling end includes at least one refrigerant supply channel and at least one refrigerant return channel 5. Mounting means are provided to secure the revolving arm with its coupling end within the inlet. These securing means include a securing screw for pressing the connector body into the inlet. The clamping screw extends out of the clamping end of the revolving arm, where 10 has a bolt head that can be hooked and unhooked to a support surface on the clamping arm by rotating the clamping bolt about its central axis. A threaded cover is screwed into one threaded end of the set screw to exert a set force on the set screw. According to one aspect of the present invention, the coupling end is formed by a solid connector body, which is connected to the tubular structure of the revolving arm and has a front end and a rear end. A perforation extends axially from the front end to the rear end, with at least one said coolant supply channel and at least one said coolant return channel being disposed in the connector body about the perforation. The set screw is rotatably engaged within the bore and its threaded end extends into the bore shape at the rear end of the connector body. The threaded wrap 25, which is screwed over the threaded end, rests on a bearing surface at the rear end of the connector body to exert the clamping force on the set screw. The tubular structure of the revolving arm comprises an arm support tube, which is connected to the rear end of the connector body, and a gas conduit tube, which is disposed within and interacts with the arm support tube to define between them. a small annular cooling space to channel refrigerant gas from the shaft to the free end of the revolving arm. The inner section of the gas conduit pipe 5 forms a return channel for the refrigerant gas. The refrigerant supply and return means include at least one refrigerant supply channel and at least one refrigerant return channel disposed in the solid connector body around the bore. At the rear end of the solid connector body, at least one said refrigerant supply channel is in communication with the return channel.

A preferred embodiment of the screw head is, for example, the shape of a hammer head defining a protruding surface on each side of the handle, wherein the hammer head rests with both protruding surfaces on the bearing surface on the joint. revolving arm attachment. However, the screw head may of course also be in the form of a single hook defining only a single projecting surface. It may also have a more complicated shape, provided it is still capable of being hooked and unhooked from a bearing surface on the arm clamping joint by rotating the clamping screw around its central axis.

For easy tightening or loosening of the threaded wrap that rests on the bearing surface at the rear end of the connector body and for easy verification that it, for example, has not been loosened, the securing means further comprises a safety tube. drive fixed at a first end to the threaded wrap and extending all over the revolving arm to the free end thereof, where its second end supports a coupling head so that a drive key is coupled to it to transmit torque to the threaded wrap through of the drive tube. Alternatively, the coupling head for coupling to it a drive key could be fixed directly to the threaded wrap, that is, without the drive tube permanently attached to the threaded wrap. This workaround would, however, make it more difficult to couple a drive key to the wrapper and to verify that the threaded wrapper is sufficiently tightened.

The set screw is advantageously connected to a positioning tube extending through the entire revolving arm to the free end thereof. The positioning tube allows for easy positioning of the set screw, to lock it in place when torque is exerted on the screw cap and to check the angular position of the screw head. The positioning tube is advantageously coaxial and rotatably supported within the drive tube, that is, it no longer takes up space within the tubular structure of the revolving arm.

The revolving arm tubular structure usually includes an arm support tube, the connector body being connected to one end of the arm support tube and its other end 20 being closed by an end cap. The drive tube then extends axially through the armrest tube and its free end is rotatably supported in a sealing manner in a perforation of the end cap. This arrangement allows, for example, to visually inspect the position of the screw head of the drive and positioning pipes without gas leakage through the front end of the arm.

Rather than having a tubular coupling end, as with all prior art revolving arms, the revolving arm has a solid connector body which is advantageously a cast body attached to the tubular structure of the revolving arm, with the holes in which the revolving arm is provided. The cylindrical body portion is engaged and at least one refrigerant supply channel and at least one refrigerant return channel are provided as perforations in said solid cast body (comprising straight perforations and composite perforations). It should be noted that such a connector body, which can be manufactured without the need for complicated casting molds, is a particularly compact, sturdy and secure connecting means for connecting the revolving arm to the vertical rotary shaft.

In a preferred embodiment of FCM, compartment one

first integral concave conical seating surface located proximal to its bottom surface and a concave cylindrical guiding surface located closest to the housing inlet opening, and the connector body has a first convex conical backrest surface and a guiding surface convex cylindrical surface interacting with said concave conical seating surface, said concave cylindrical orientation surface respectively in the compartment. More particularly, the cylindrical guiding surfaces interact with one another to orient the connector body of the revolving arm 20 axially by placing or withdrawing it from a position in which the connector body rests with its first convex conical counter-seating surface on the first seating surface. concave conical. It should be noted that the axial orientation provided by the two cylindrical guiding surfaces considerably reduces the risk of damage to the connector body or housing during the final coupling operation. When the connector body is seated in its housing, its first convex conical back seat surface interacts with the first concave seat surface to provide a first sealing function between the connector body and the housing near the bottom of the housing. This first sealing function allows, for example, to provide a refrigerant gas connection at the front end of the connector body.

The housing advantageously has on it a second concave conical seating surface, with the concave cylindrical guiding surface resting between the first concave conical seating surface and the second concave conical seating surface. The connector body has on it a second convex tapered backing surface, with the convex tapered guiding surface resting between the first convex tapered backing surface and the second convex tapered backing surface. During insertion of the connector body into the housing, the outer concave conical seating surface first guides the connector body in axial alignment with the cylindrical orienting surface. When the connector body is seated in its housing, its second convex conical back seat interacts with the second concave conical seating surface to provide a second sealing function between the connector body and the housing near the housing inlet. This second sealing function allows, for example, to provide a sealed refrigerant gas connection on the cylindrical guiding surfaces.

Thus, with the configuration described in the preceding paragraph, at least one refrigerant gas channel is advantageously arranged in the revolving arm clamping joint having an opening in the concave cylindrical guiding surface; and at least one refrigerant gas channel is then disposed in the connector body of the revolving arm having an opening in the convex cylindrical guiding surface, with the apertures overlapping when the connector body is accommodated in its seats in the housing. The revolving arm fastener advantageously comprises a ring-shaped cast body made of refractory steel, with the compartments arranged radially in the ring-shaped cast body. It should be noted that such revolving arm clamping joint is a particularly compact, sturdy and secure connecting means for connecting the revolving arm to the vertical rotary shaft.

The shaft advantageously includes a support structure consisting of the revolving arm clamping joints and intermediate support tubes which are interposed as loading members of 10 structural loads between the revolving arm clamping joints described in the preceding paragraph. The revolving arm clamping joints and intermediate support tubes are preferably assembled by welding. It should be noted that such an axle can easily be manufactured at relatively low costs using conventional elements. It 15, however, offers a sturdy and durable support structure that has very good temperature and corrosion resistance in the crucible chambers.

At least one section of the shaft extending between the two adjacent crucible chambers comprises: an intermediate support tube 20 fixed between two arm clamping joints to form an outer wrapper; an intermediate gas conduction wall disposed within the intermediate support tube to delimit an annular main refrigerant gas supply channel therebetween; and an inner gas conduction wall within the intermediate support pipe 25 to delimit an annular main refrigerant gas distribution channel therebetween, with the inner gas conduction wall further defining the outer wall of a central discharge channel. . Such a three-concentric refrigerant gas shaft section ensures excellent cooling of the outer wall of the shaft section, ie the intermediate load support pipe. This in effect forms the outer wall of the main refrigerant supply channel through which the entire refrigerant supply stream is channeled before being distributed to the revolving arms.

The arm locking joint advantageously comprises a

ring-shaped cast body comprising: at least one of the compartments for receiving the revolving arm connector body therein; a central passageway forming the central outlet channel for refrigerant gas within the arm clamp joint; first secondary passages 10 arranged in a first ring section of the melt to provide gas passages for refrigerant gas flowing through the annular main refrigerant gas distribution channel; second secondary passages disposed in a second ring section of the molten body to provide gas passages for refrigerant gas flowing through the annular main refrigerant gas supply channel; a first conduit means disposed in the molten body so as to interconnect the annular main refrigerant gas supply channel with a gas outlet opening within at least one compartment; and a second channeling means disposed in the molten body so as to interconnect a gas inlet opening within at least one compartment with the central passageway. The first channeling means advantageously comprises at least one oblique hole extending through the ring-shaped cast body from the second ring section to a side surface delimiting the housing. The second channeling means advantageously comprises an axially extending perforation of the housing. This arm clamp joint mode combines a low pressure drop refrigerant gas distribution on the shaft and a rigid revolving arm attachment to the shaft in a very compact and economical design. With its integrated gas passages, it contributes substantially to the fact that the vertical rotary shaft, which includes three coaxial cooling channels, can be manufactured using a very small number of standard elements. It also contributes to ensuring a strong and durable support structure with very good temperature and corrosion resistance in the crucible chambers.

A layer of microporous thermal insulator is advantageously disposed in the arm support tube; and a metal protective cover covers the micro-porous thermal insulation. The metal revolving teeth 10 are in this configuration advantageously welded directly to the metal protective cover, and anti-rotating means are then disposed between the arm support tube and the metal protective cover.

Brief Description of Drawings

Further details and advantages of the present invention will be

apparent from the following detailed description of a preferred but non-limiting embodiment with reference to the accompanying drawings, in which:

Fig. 1 is a three-dimensional view of a multi-crucible furnace according to the invention with a partial section;

Fig. 2 is a schematic diagram illustrating the flow of refrigerant through the rotating hollow shaft and revolving arms;

Fig. 3 is a section through a rotating hollow axis, drawn as a three-dimensional view,

Fig. 4 is a three-dimensional view of a fastening joint of

revolving arm, with four revolving arms attached to it, Fig. 5 is a first section through an entry into a revolving arm joint with a connector body of a revolving arm received by it (section is drawn as a three-dimensional view) ,

Fig. 6 is a second section through an inlet on a revolving arm fastener joint with a connector body of a revolving arm received by it (the section is drawn as a three-dimensional view), and

Fig. 7 is a section through a free end of a revolving arm (the section is drawn as a three-dimensional view).

Description of preferred embodiments

Fig. 1 shows a multi-crucible furnace or roasting furnace 10. Both the construction and operation of such a multi-crucible furnace (FCM) 10 are known in the art and are therefore described here only when relevant to the illustration of the inventions. claimed here.

The FCM as shown in Fig. 1 is basically an oven that includes several crucible chambers 12 arranged one above the other. The FCM shown in Fig. 1 includes, for example, eight numbered crucible chambers 12i, 122 ... 128. Each crucible chamber 12 includes a substantially circular crucible 20 (see, e.g., 14], 142). . These crucibles 14 have alternatively several material drop holes 16 along their outer peripheries, such as, for example, crucible 142, or a central material drop hole 18, such as, for example, crucible M1 .

Reference numeral 20 identifies a vertical rotary hollow shaft disposed coaxially with central axis 21 of oven 10. That axis 20 passes through all crucible chambers 12, with crucibles without central material drop hole 18 - such as, e.g., the crucible 142 in Fig. 1 has a central axis passageway 22 to allow axis 20 to extend freely therethrough. In crucibles with central material drop holes 18 - such as, for example, the crucible 14t in Fig. 1 and axis 20 extends through the central material drop hole 18. It should be noted that in this context the drop hole Central material 18 has a much larger diameter than that of axis 20, so central material drop hole 18 is in fact an annular opening around axis 20.

Both ends of the shaft 20 comprise a shaft end rotatably supported on a support (not shown 10). Rotation of the axis 20 about its central axis 21 is achieved by means of a rotary drive unit (not shown in Fig. I). Such rotary drive unit for shaft 20, as well as shaft supports, is known in the art and, no longer relevant to understanding the inventions claimed herein, will not be described in greater detail herein.

Fig. 1 also shows a revolving arm 26 which is fixed in the crucible chamber 122 to a revolving arm fastening joint 28 on axis 20. Such an arm clamping joint 28 is disposed in each crucible chamber 12 where it normally supports more than one revolving arm 26. 20 In most FCM, such arm clamping joint 28 typically supports four revolving arms 26, the angle between two successive revolving arms 26 being 90 °. Each revolving arm includes a plurality of revolving teeth 30. These revolving teeth 30 are designed and arranged to move material in the crucible 25 towards its center or periphery as the shaft 20 is rotated. In a crucible chamber with peripheral material drop holes 16 in its crucible 14, such as, for example, the crucible chamber 122, these revolving teeth 30 are designed and arranged to move the material in the crucible toward the crucible holes. peripheral material drop 16 when axis 20 is rotated. In a crucible chamber with a central material drop hole 18 in its crucible 14, such as, for example, the crucible chamber 12j, these revolving teeth are designed and arranged to move material in the crucible 14 toward the crucible. 5 central materials drop hole 18 when the shaft is rotated in the same direction.

A brief description of the material flow through FCM 10 is now given. To heat or roast materials within FCM 10, this material is discharged from a conveyor system (not shown) through oven loading openings 32 to inside the highest crucible chamber 12i of the FCM. In this chamber 12t, the material falls onto the crucible M1, which has a central material drop hole 18. As the shaft continuously rotates, the four revolving arms 26 in the crucible chamber push the material with their revolving teeth 30 over it. the crucible 14i toward and into its central material drop hole 18. Through this the material falls onto the crucible 142 of the next crucible chamber 122. There the revolving arms 26 push the material with its revolving teeth over the crucible 142 towards its peripheral material drop holes 16. Through these, the material falls onto the next crucible (not shown in Fig. 1) which again has a central material drop hole 18. Thus, the material which enters FCM 10 through oven loading port 32 through all eight crucibles 14j ... 148 through rotation of revolving arms 26. Arriving in lower crucible chamber 128, the mat Swollen or heated material finally leaves the FCM 10 through an oven discharge opening 34.

As is well known in the art, both shaft 20 and revolving arms 26 have internal channels through which a gaseous refrigerant, generally pressurized air, circulates, which will hereinafter be referred to as "refrigerant" for simplicity. The purpose of this refrigerant is to protect shaft 20 and revolving arms 26 from damage due to the high temperatures in the crucible chambers 12. In fact, within the crucible chambers 12 the ambient temperature can reach 100 ° C.

The flowchart of Fig. 2 provides a schematic overview of a new and particularly useful gas cooling system 40 for axis 20 and revolving arms 26. The large dashed rectangle 10 schematically depicts FCM 10 with its eight crucible chambers 10 12 ... 128. A schematic representation of the rotary hollow shaft 20 illustrates the refrigerant gas flow passages within the axis 20. The reference numerals 26'i ... 26'8 identify in each crucible chamber 12i. 128 is a schematic representation of the cooling system of a revolving arm disposed in the respective crucible chamber. Small dashed rectangles 15] ... 288 are schematic representations of the revolving arm fixing joints on the shaft 20.

Reference numeral 42 in Fig. 2 identifies a source of refrigerant gas, such as a blower that pressurizes ambient air. As is known in the art, fan 42 is connected by means of a lower refrigerant gas supply line 46 'to a lower refrigerant gas inlet 44' of axis 20. This lower refrigerant gas inlet 44 'is disposed outside the 10 below the lower crucible chamber 128. However, in FCM 10 of Fig. 2, fan 42 is also connected via an upper refrigerant gas supply line 46 ”to an upper refrigerant gas inlet 44”. This upper 44 ”refrigerant gas inlet is disposed outside the oven 10 above the highest crucible chamber 12]. As a result, the flow rate from the fan 42 is divided between the lower refrigerant gas inlet 44 'to be supplied to the lower half of the shaft 20 and the upper refrigerant gas inlet 44' to be supplied to the upper half of the shaft. axis 20. It should be noted that - as axis 20 is a rotary axis - both refrigerant gas inlets 44 'and 44 ”must be rotary connections. As such rotary connections are known in the art and as their designs are no longer relevant to understanding the inventions claimed herein, the construction of the lower and upper refrigerant inlets 44 ', 44' will no longer be described here in greater detail.

Axis 20 includes three concentric refrigerant channels within an outer casing 50. The outermost channel is a 10 annular main refrigerant gas supply channel 52 in direct contact with the outer casing 50 of axis 20. This main supply channel Annular 52 involves an annular main distribution channel 54, which ultimately involves a central discharge channel 56.

It should be noted that between the crucible chambers 124 and 125, 15 that is, approximately in the middle of the shaft 20, partitioning means such as a flange 58, part the annular main supply channel 52 and the channel annular main distribution 54 into a lower half and an upper half. This partition however does not affect the central discharge channel 56, which extends from the lower crucible chamber 128 through

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all the crucible chambers 128 to 12] to the top of the axis 20. It is necessary henceforth to distinguish between the lower and upper half of the annular main supply channel 52, respectively between the lower and upper half of the channel. annular major distribution 54, where the lower half will be identified with the envelope (') and the upper half 25 with the envelope (”).

The lower refrigerant gas inlet 44 'is directly connected to the lower half 52' of the annular main supply channel 52. The refrigerant supplied to the lower refrigerant gas inlet 44 'consequently enters the lower crucible chamber 128 into the lower crucible. lower annular main supply channel 52 'and is then channeled therethrough up to the partition flange 58 between the crucible chambers 125 and 124, with the refrigerant gas flow rate remaining invariable over the entire length of the channel of 5 lower annular main supply 52 '. This constant flow rate of refrigerant gas throughout the length of the lower annular main supply channel 52 'ensures that the outer casing 50 of axis 20 is efficiently cooled in the four lower crucible chambers 128 ... 125.

Just below partition flange 58 is a gas passage

lower refrigerant 60 'between lower annular main main supply channel 52' and lower annular main main distribution channel 54 '. Through this lower refrigerant gas passage 60 ', the refrigerant gas enters the lower annular main distribution channel 54'. Through at least one 625 ... 628 refrigerant gas supply channel in its 285 ... 288 revolving arm clamping joint, each revolving arm cooling system 26'5 ... 26'8 in the lower half FCM 10 is in direct communication with the lower annular main distribution channel 54 '. Through at least one 645 ... 20 648 refrigerant gas discharge channel in its revolving arm clamping joint 285 ... 288, each revolving arm cooling system 26'5 ... 26'8 in the lower half of the FCM 10 is also in direct communication with the central discharge channel 56. Consequently, at the revolving arm clamping joint 285, a secondary refrigerant gas stream branches from the main refrigerant gas stream 25 in the lower main distribution channel. 54 'and is recirculated through the revolving arm cooling system 26's to be then evacuated directly into the central discharge channel 56. In revolving arm clamping joint 286, another portion of the gas flow in the annular main distribution channel 54 'passes through the revolving arm cooling system 26'6 and is then also evacuated to Finally, at the last revolving arm retaining gasket 28g, all remaining gas flow in the lower main distribution channel 54 'passes through revolving arm cooling system 26'8 and is It is then evacuated into the central outlet channel 56.

The flow system in the upper half of shaft 20 is very similar to the flow system described above. The 44 ”upper refrigerant inlet is directly connected to the upper half 52” of annular mains supply channel 52. The refrigerant supplied to the 44 ”upper refrigerant inlets therefore enters the upper annular mains supply channel 52” above highest crucible chamber 12) and is then channeled therethrough down to the partition flange 58 between the crucible chambers 124 and 125, the refrigerant flow rate remaining unchanged over the entire length of the main supply channel. upper ring 52 ”. This constant refrigerant gas flow rate over the entire length of the 52 ”upper annular main supply channel ensures that the outer shaft wrap 50 of the shaft is efficiently cooled in the four upper crucible chambers 12] ... 124.

Just above the partition flange 58, there is an upper 60 ”refrigerant gas passage between the upper main supply channel 52” and the upper annular main distribution channel 54 ”. Through this 60 ”upper refrigerant gas passage, the refrigerant gas enters upper main distribution channel 25” 54 ”. The connection of each revolving arm cooling system 26'4 ... 26'i in the upper half of oven 10 to the upper main distribution channel 54 ”and central discharge channel 56 is as described above for the refrigeration systems. revolving arms 26'4 ... 26'j in the lower half. Consequently, at the revolving arm clamping joint 284, a secondary refrigerant gas flow branches from the main refrigerant gas flow in the upper 54 ”top distribution channel and is fed back through the revolving arm cooling system 26'4 to then be evacuated 5 directly into main discharge channel 56. At revolving arm retaining gasket 283, another portion of the gas flow in the upper main distribution channel 54 ”passes through revolving arm cooling system 26'3 and is then also evacuated into main discharge channel 56. Finally, at the highest revolving 10-arm clamping joint 281, all remaining gas flow in the upper main distribution channel 54 ”passes through the refrigeration system. 26 'revolving arm! and is then evacuated into the main discharge channel 56. From the main discharge channel 56, the exhaust gas stream is then evacuated directly into the atmosphere or is evacuated via a rotary connection into a pipe to a controlled gas evacuation (not shown).

Fig. 3 illustrates a particularly advantageous embodiment of the rotary hollow shaft 20 of the furnace. Fig. 3 more particularly shows a longitudinal section through the central part of the shaft 20. This central part 20 includes the aforementioned partition flange 58 which divides the annular main supply channel 52 and the annular main distribution channel 54 into a lower half 52 ', 54' and an upper half 52 ”, 54” respectively.

Outer casing 50 of the shaft mainly consists of 25 intermediate support tubes 68 interconnected by the revolving arm clamping joint 28. Such revolving arm clamping joint 28 comprises a ring-shaped cast body 70 made of refractory steel. Intermediate support tubes 68 are made of thick-walled stainless steel tubes and are designed as structural load loading members between successive revolving arm clamping joints 28. Intermediate support tubes 68 interconnected by large revolving arm clamping joints 28 constitute the axle load-bearing structure 20, which supports revolving arms 26 and 5 to absorb critical torque when revolving arms 26 are pushing material. It should further be noted that - unlike the prior art axes - the outer wrap 50 described herein is advantageously a welded frame, the ends of the intermediate support tubes 68 are welded to the arm clamping joints. revolvers 28 rather than being flanged there.

As explained above, the shaft section extending between adjacent crucible chambers 124 and 125 (i.e. the center shaft section) is somewhat particular in that it comprises the partition flange 58 as well as the 15 cooling passages 60 ', 60 ”between annular main supply channel 52 and annular main distribution channel 54. Before describing this particular central axis section, a" normal "axis section will now be described, also with reference to Fig. 3. Such "normal" shaft section extending between two other adjacent crucible chambers, such as for example crucible chambers 123 and 124, comprises intermediate support tube 68 welded between two clamping joints arms 283 and 284 to form the outer wrap 50 of the shaft 20. The intermediate support tube 68 also delimits the annular main supply channel 52 externally, which ensures very good cooling of the intermediate support pipe 68. An intermediate gas conduction wall 72 is disposed within the intermediate support pipe 68 to delimit the supply channel 52 internally and the annular main distribution channel 54 externally. An integral gas conduction wall 74 is disposed within the intermediate gas conduction wall 72 to delimit the distribution channel internally and the main outlet channel 56 externally. The intermediate gas conduction wall 72 comprises a first pipe section 721 and a second pipe section 722. The first pipe section 72] is welded at one end to the clamping joint 284. The second pipe section 722 is similarly welded at one end to the clamping joint 283 (not shown in Fig. 3). The first tubing section 71] and the second tubing section Il1 have opposite free ends which are arranged opposite each other. A sealing cover 76 is secured to the free end of the first pipe section 11 \ by sealingly engaging the free end of the second pipe section Il1, and simultaneously tolerates the relative movement of both pipe sections 721 and Il1 in the axial direction. . It follows that an expansion joint is formed in the intermediate gas conduction wall 72. This expansion junction allows to compensate for the differences in thermal expansion of the intermediate support tube 68 and the intermediate gas conduction wall 72 as it generally remains cooler than the intermediate support pipe 68. The integral gas conduction wall 74 similarly comprises a first pipe section 74] and a second pipe section 742. The first pipe section 74! is welded at one end to the clamping joint 284. The second pipe section 742 is similarly welded at one end to the clamping joint 283 (not shown in Fig. 3). First tubing section 74) and second tubing section 742 have opposite free ends which are disposed opposite each other. A sealing cover 78 is attached to the free end of the first pipe section 74] and seals into the free end of the second pipe section 742 while tolerating the relative movement of both sections 74] and 742 in the axial direction. The result is that an expansion joint is formed in the internal gas conduction wall 74. This expansion joint allows to compensate for the thermal expansion differences of the intermediate support tube 68 and the internal gas conduction wall 74, which generally remains longer. It should be noted further that the solution with the two sealing caps 76, 78 makes welding the shaft sections much easier by welding.

As can be seen from Fig. 3, the shaft section extending between the adjacent crucible chambers 124 and 125 is distinct from the "normal" section described in the preceding paragraph in several respects. The intermediate support tube 68 consists, for example, of two halves 68j and 682 which are mounted at the level of the partition flange 58 (in effect, each pipe half 68! And 682 includes an annular end flange 581 and 582 and both annular flanges 58i and 582 are welded together). The intermediate cover 72 'simply consists of two pipe sections 72'1 and 72'2, with a first end of each pipe section 72'1 and IT1 welded to one of two arm clamping joints 283 and 284, and the second end being a spaced free end of the partition flange 58 for defining gas passages 60 'and 60' between lower annular main supply channel 52 'and lower annular main distribution channel 54', respectively. upper annular main supply 52 ”and upper annular main distribution channel 54”. Inner cover 74 'consists of four tubular sections 74'1, 74'2, 74'3, 74'4, with the first tubing section 74'1 being welded at one end to arm clamp 284, second pipe section 25 74'2 is welded at one end to flange 58i, third pipe section 74'3 is welded at one end to flange 582, and fourth pipe section 74'4 is welded at one end to joint A first sealing cover 80 provides a sealed connection and an axial expansion joint between opposite free ends of the first pipe section 74'i and the second pipe section 74'2. A second sealing cover 82 provides a sealed connection and an axial expansion joint between opposite free ends of the third pipe section 74'3 and the fourth pipe section 574'4. Sealing covers 80 and 82 function like sealing covers 76 and 78 and make mounting the center shaft section much easier.

To complete the thermal protection of shaft 20, it is advantageously covered with a thermal insulator (not shown). Such a shaft insulator 20 is advantageously a multilayer insulation, e.g., an inner refractory layer of micro-porous material, a thicker intermediate layer of insulating fusible material and an even thicker outer refractory layer of dense fusible material.

A preferred embodiment of a revolving arm clamping joint 28 is now described with reference to Fig. 3 and Fig. 4. As already discussed above, revolving arm clamping joint 28 comprises a ring-shaped cast body 70 Made of refractory steel. The central passage 90 in this ring-shaped body 70 forms the central exhaust channel 56 for the refrigerant gas within the revolving arm fastener gasket 28. First secondary passages 92 are disposed in a first ring section 94 of the shaped body 70 around the central passage 90 to provide gas passages for the refrigerant gas flowing through the annular main distribution channel 54. Secondary secondary passages 96 are disposed in a second ring section 25 of the shaped body 70 around the first ring section 94 to provide gas passages for the refrigerant flowing through the annular main supply channel 52. For each revolving arm 26 to be connected to revolving arm retaining gasket 28 , the ring-shaped body 70 further includes a housing 100, i.e. a \

radially inwardly extending cavity 70 of the ring-shaped body 70 between said first and second passages 92 and 96. The revolving arm clamping joint 28 includes four compartments 100, the angle between the central axis being two consecutive compartments 100 590 °. Oblique holes 102 in the ring body 70 (see Fig. 5), which have an inlet opening 102 'in the second ring section 98 of the ring body 70 and an outlet opening 102 ”on a side surface of the compartment 100 form the refrigerant gas supply channels 62, which have already been mentioned within the context of the description of Fig. 3. A perforation 104 in the ring-shaped body 70, axially extending from the compartment 100, forms the conduit channel. refrigerant gas 64, which has already been mentioned within the context of the description of Fig. 3.

Referring now more particularly to Fig. 3, Fig. 5 and Fig. 6, it may first be observed that the revolving arm 26 includes a connector body 110 which forms a coupling end of the revolving arm 26 received in housing 100 of the housing. revolving arm fixing joint 28 (see Figs. 3 and 5). The connector body 110 is a solid cast body with several holes in it, and is advantageously made of refractory steel 20. The housing 100 has two concave conical seating surfaces 112, 114 separated by a concave cylindrical guiding surface 116. The connector body 110 has two convex conical counter seating surfaces 112 ', 114' separated by a guiding surface convex cylinder 116 '. All of these 25 conical surfaces 112, 114, 112 ', 114' are annular surfaces of a single cone, that is, they have the same conical angle. This tapered angle should normally be greater than 10 ° and less than 30 ° and is normally in the range of 18 ° to 22 °. When the connector body 110 is inserted axially into the housing 100, the convex conical backseat surface 112 'is pressed against the concave conical seat surface 112 and the convex conical backseat surface 114' is pressed against the convex conical seat surface 112 '. concave conical seating surface 114.

When attaching a new revolving arm 26 to the axis 20, the connector body 110 of the revolving arm 26 must be inserted into the housing 100 of the revolving arm clamping joint 28. During this introduction movement, the outer concave conical seat surface 114 first orienting the connector body 110 in axial alignment with the cylindrical guiding surface 116. Thereafter both guiding surfaces 116 and 116 'interact with each other to axially orient the connector body 110 to its final seat position in housing 100. It should be noted that the axial orientation provided by the two cylindrical guiding surfaces 116 and 116 'considerably reduces the risk of damage to connector body 110 or housing 100 during the final coupling operation.

The revolving arm 26 further comprises an arm support tube 120 welded at one end to a protruding surface 122 on the rear side of the connector body 110. This arm support tube 120 must withstand the forces and torques acting on the revolving arm. It 20 advantageously consists of a thick-walled stainless steel tube that extends the full length of the revolving arm 26. A gas conduction tube 124 is disposed within and interacts with the arm support tube 120 to define it. between them a small annular cooling space 126 for channeling the refrigerant gas 25 to the free end of the revolving arm 26. The inner section of the gas conduction tube 124 forms a central return channel 128 through which the refrigerant gas flows from from the free end of the revolving arm 26 back to the connector body 110. It should be noted that one end of the gas conduction pipe 124 is welded to a cylindrical extension 130 on the rear side of the connector body 110. The diameter of the cylindrical extension is smaller than that the inside diameter of the armrest tube 120 so that a The annular chamber 131 remains between the cylindrical extension 130 and the armrest tube 120 surrounding the cylindrical extension 130. This annular chamber 131 is in direct communication with the small annular cooling spacing 126 between the gas conduction tube 124 and the arm support tube 122.

As already explained above, the connector body 110 is a

solid cast comprising several holes which will now be described. In Fig. 6, reference numeral 132 identifies a central bore that extends axially through the connector body 110, from an end face 134 in the cylindrical extension 130 to a front face 136 on the front side 15 of the connector body 110. The purpose of this central hole 132 will be described below. Reference numeral 140 in Fig. 6 identifies gas return holes disposed in connector body 110 around central hole 132 and which have inlet openings 140 'at the end face 134 and outlet openings 140 ”in the front face 136 of the body connector 110 (there are four 20 of these gas return holes 140 disposed about central hole 132). These gas return holes 140 form communication channels between the return channel 128 in the revolving arm 26 and a gas outlet chamber 142 which remains in the housing 100 between the front face 136 of the connector body 110 and a lower surface 144 of the housing. 100 25 when the connector body 110 is accommodated there. From that gas outlet chamber 142, the refrigerant gas returning from the revolving arm 26 overflows through the bore 104 into the central passage 90 of the revolving arm clamping joint 28, i.e. into the central discharge channel 56 Reference numeral 146 in Fig. 5 identifies four gas supply holes disposed in the connector body 110. These gas supply holes 146 have inlet openings 146 'in the convex cylindrical guiding surface 116' of the connector body. 110 and outlet openings 146 ”in the cylindrical surface of cylindrical extension 5 130. It should be noted that the inlet openings 146 'in the convex cylindrical guiding surface 116' overlap the gas outlet openings 102” of the oblique holes 102 in the body. 70. It is recalled in this context that these oblique holes 102 form the canes cooling gas supply rings 62 of the revolving body 26 in the gasket of 10 revolving arm attachment 28. Consequently, when the connector body 110 is accommodated in its housing 100, the gas supply holes 146 form communication channels in the connector body 110 between the annular chamber 131, which is in direct communication with the small annular cooling opening 126 in the revolving body 26, and the refrigerant gas supply for the revolving arm 26 in the revolving arm fixing joint 28. It should be noted that a positioning pin 148 at the front end of the connector body 110 interacts with a positioning hole in the lower surface 144 of housing 100 to ensure angled alignment of inlet openings 20 'in convex cylindrical guiding surface 116' of connector body 110 with 102 ”gas outlet openings on the surface ie concave cylindrically oriented 116 in housing 100 when connector body 110 is inserted into housing 100. To seal the gas passages between the revolving arm retainer gasket 28 and connector body 110 in housing 100, the counter surfaces Convex tapered seats 112 ', 114' of connector body 110 are advantageously equipped with one or more temperature resistant sealing rings (not shown). Further, to improve the sealing function of convex conical backseat surfaces 112 ', 114' in housing 100, they are advantageously coated with a temperature resistant sealing paste.

Referring now to Fig. 6, preferred new fastening means for securing connector body 110 in its 100 compartment will now be described. These new securing means comprise a securing bolt 150. It comprises a cylindrical bolt body 152 loosely engaged in the central bore 132 of the connector body 110. That bolt body 152 supports on the front side of the connector body 110 a bolt head 154, which advantageously has the form of a hammerhead defining protruding surfaces 156 ', 156 ”on each side of the body 152. At the rear side of the connector body 110, the screw body 152 has a screw end 158. The means Preferred fasteners shown in Fig. 6 further comprise a threaded bushing 160 (or a conventional nut) which is screwed onto the threaded screw 158 extending out of the central bore 132 of the connector body 110 on the rear side thereof.

Fig. 6 shows the axial clamping device in a clamping position in which it firmly presses the connector body 110 into the housing 100. At that clamping position, the 20 threaded cover 160 rests against a bearing surface. on the rear side of the connector body 110. This bearing surface corresponds, for example, to the extreme surface 134 of the cylindrical extension 130 of the connector body 110. On the other side of the connector body 110, the screw body 152 extends through the chamber gas outlet 142 and bore 104 in the bottom of the housing 100 into the center passage 90 of the revolving arm clamping joint 28. Here, the hammer head 154 of bolt 150 is in a hooked engagement with a bearing surface 162 on the arm clamp joint with its two protruding surfaces 156 ', 156 ”resting against the bearing surface 16 2. It should be noted that the set screw 150 is sufficiently preloaded, that is, the threaded bushing 160 is tightened to a predetermined torque to ensure that the connector body 110 is always firmly pressed into the housing 100 during FCM operation.

When one of the revolving arms 26 is disassembled, the

retaining screw 150 is withdrawn with the revolving arm 26, that is, it remains in the connector body 110 of the revolving arm 26. In order to be able to extract the hammer head 154 through the hole 104 in the bottom of the housing 100, this hole has the shape of a keyhole having a shape that roughly corresponds to the cross section of the hammerhead 154. The result is that by turning the hammerhead 154 by 90 ° about the central axis of the screw body 152, the head hammer 154 can be brought from the "hooked position" shown in Figure 6 to the "unhooked position", in which it can be drawn axially through the keyhole 104 into compartment 100. Similarly, when a new revolving arm 26 is mounted, hammerhead 154 will first be in a position where it can pass through the bur Once the connector body 110 is accommodated in its housing 100, the hammer head 154, which will now be located on the other side of the keyhole 104, may be brought into the "hooked position" shown in Fig. 6 by turning the hammer head 154 by 90 ° about the central axis of the screw body 152. It should also be noted that in the "hooked position" of the set screw 150 25 shown in Fig. 6, the head Hammer 154 leaves a very large outlet opening for the refrigerant gas flowing through the keyhole 104 into the central gas passage 90.

The clamping device shown in Fig. 6 also comprises drive and positioning means for tightening / loosening and positioning it from a secure position outside the FCM. Such drive means will now be described with reference to Figs. 6 and 7. In Fig. 6, reference numeral 170 identifies a drive tube that is fixed (e.g. welded) with one end to threaded bushing 160. Reference numeral 172 identifies a positioning tube that is fixed with one end to the screw body 152 (e.g. by means of a screw 173 welded to the rear end of the positioning tube as shown in Fig. 6). Referring now to Fig. 7, it can be seen that both the drive tube 170 and the positioning tube 172 extend axially through the intermediate support tube 120 up to the free end thereof. Here both the front end of the drive tube 170 and the front end of the positioning tube 172 include a coupling head 174, 176 for coupling to it a drive key (not shown). Both coupling heads 174, 176 may, for example, include a hexagonal inlet as shown in Fig. 7. Coupling head 174 of drive tube 170 is rotatably supported in a central bore 178 of an end cap 180 and sealed 178. The end cap 180 comprises on its rear side 20 a first flange 182 that closes the front end of the intermediate support tube 120 and on its front side a second flange 184 that closes the front end of an outer metal protective cover. 186, which will be described below. Positioning tube 172 is rotatably supported with drive tube 170. A blind flange 25 188 is connected to the front face of the second flange 184 of the end cap 180 so as to close the central bore 178 in the end cap 180. thermal insulation is inserted between the coupling head 174 and the blind flange 188. Reference numeral 192 identifies a positioning pin fixed to the blind flange 188. This positioning pin 192 extends through the insulating cap 190 for support (see figures ) at one end over the coupling head 174, thereby preventing loosening of the threaded bushing 160.

After removal of the blind flange 188 and thermally insulating cap 190, the coupling heads 174, 176 of the drive tube 170 and positioning tube 172 are accessed. The drive tube 170 is used to tighten the threaded bushing. 160. Positioning tube 172 serves primarily as an indicator of the position that hammerhead 154 has relative to key hole 104. Its coupling head 176 is therefore provided with a suitable positioning mark. It should be noted that positioning tube 172 can also be used to secure retaining screw 150 while loosening threaded bushing 160 via drive tube 170. Finally, coupling head 174 of drive tube 170 can It also has marks thereon which, in combination with the marks on the coupling head 176 of the positioning tube, allows to check whether sufficient tightening torque has been applied to the clamping device. It should be noted that the blind flange 188 may be removed during operation of the cooling system without substantial gas leaks. Indeed, the threaded bushing 160 seals the rear end of the drive tube 170 and the front end of the drive tube is sealed within the central bore 178 within the end cap 180.

The aforementioned metal protective cover 186, which is seen in Figs. 4 to 7, it covers a layer of microporous thermal insulator 194 arranged on the intermediate support tube 120. Anti-rotating means, e.g. identified by reference numeral 196 in Fig. 6, interconnect the metal protective cover 186 and the intermediate support tube 120 and prevent any rotation of the protective cover 186 around the central axis of the revolving arm 26. It should be noted that in one embodiment of the revolving arm 26 the protective cover 186 is made of stainless steel, the revolving teeth 30 which are also made of stainless steel are welded directly over the protective cover 186 (see Fig. 7 showing one of these revolving arms ).

10

15

20 multiple crucible oven

12 crucible chamber

14 crucible

16 drop hole of peripheral material

18 central material drop hole

rotary hollow shaft

22 center axis through opening

26 revolving arm

28 revolving arm fastener

revolving teeth

32 oven loading opening

34 oven discharge opening

40 gas cooling system

42 fan (refrigerant supply source)

44 'bottom refrigerant gas inlet

44 '' upper refrigerant gas inlet

46 'bottom refrigerant gas supply line

46 ”upper refrigerant gas supply line

50 Outer Wrap (Shaft)

’Entrance opening (of 102)

'Outlet opening (of 102) perforation (in 28) connector body (of 26)

first concave conical seat surface (out of 100)

second concave conical seat surface (from 100)

'First convex conical counter-seating surface (from 110)

'Second convex conical counter-seating surface (from 110)

concave cylindrical guiding surface (from 110)

'Convex cylindrical orientation surface (of 110)

arm support tube

protruding surface (of 110)

gas conduit pipe

annular cooling space (from 26)

center return channel (26) cylindrical extension (110) annular chamber (26) central hole (110) extreme face (130)

102

102 ’

104

110

112

114

112

114

116

116

120

122

124

126

128

130

131

132

134 52 lower annular main refrigerant gas supply channel (at 20)

52 'Upper Annular Main Refrigerant Gas Supply Channel (at 20)

54 main lower annular refrigerant gas distribution channel (out of 20)

54 'upper annular refrigerant main distribution channel (out of 20)

56 central discharge channel

58 partition flange

60 'bottom refrigerant gas passage

60 ”upper refrigerant passage

62 refrigerant gas supply channel (in 28)

64 refrigerant discharge channels (in 28)

68 intermediate support tube (in 20)

70 ring shaped cast body (on 28)

72 Intermediate Gas Conduction Wall (in 20)

721 first section of pipe

722 second section of pipe

76 sealing cover

74 Internal Gas Conduction Wall (in 20)

741 first section of pipe

136 front face (from 110)

140 gas return holes (from 110)

140 'inlet openings (from 140)

140 ”outlet openings (from 140)

142 gas outlet chamber

144 bottom surface (of 100)

146 gas supply holes (from 110)

146 'inlet openings (from 146)

146 ”outlet openings (from 146)

148 positioning pin

150 set screw (hammer head screw)

152 bolt body

154 Screw Head (Hammer Head)

156 ', projecting surfaces (em54)

156 ”

158 screwed end screw

160 threaded bushing

162 support surface (to 154 out of 28)

170 drive tube 742 second pipe section

78 seal cover

80 sealing cover

82 sealing cover

90 central passage (in 28)

92 first secondary passages (out of 28)

94 first ring section (at 28)

96 Secondary Passages (out of 28)

98 Second Ring Section (out of 28)

100 compartments (in 28)

102 oblique holes (in 28)

172 positioning tube

174 coupling head (out of 170)

176 coupling head (on 172)

178 center drilling (in 180)

180 extreme cover

182 first flange (from 180)

184 second flange (from 180)

186 External Metal Protective Cover (on 28)

188 blind flange (at 180)

190 thermal insulating cover (in 180)

192 positioning pin (at 180)

194 microporous thermal insulating layer (out of 26)

196 Anti-Rotation Media (out of 26)

Claims (21)

1. Multiple crucible rod comprising: a vertical rotary hollow shaft (20) including at least one revolving arm fastening joint (28), at least one revolving arm (26) including a tubular structure (120, 124, 186) for circulating therein a refrigerant and a coupling end which is fitted as a socket in a housing (100) to said arm clamping joint (28), said coupling end including supply and return means. fluid, and securing means for securing said revolving arm (26) with its coupling end to said housing (100), said securing means including: • a securing screw (150) for pressing a connector body (110) into said housing (100), said securing screw (150) extending outwardly from the end coupling of said revolving arm where it has a screw head (154) which can be set by rotating said securing screw (150) about its central axis in a position of engagement or disengagement with a bearing surface on said arm clamping joint (28), and • a threaded bushing (160) bolted over a threaded end (158) of said clamping screw (150) to exert a clamping force on said clamping screw (150) and wherein said coupling end has a hole (132) into which said set screw (150) is rotatably engaged so that its screwed end (158) extends outwardly through said hole (132), and said threaded bushing (160), which is screwed over said screwed end (158), rests on a bearing support surface A coupling end for exerting said clamping force on said clamping screw (150), characterized in that: said coupling end is formed by said solid connector body (110) having a front end and a rear end; said tubular structure (120, 124, 186) of said revolving arm (26) comprises an arm support tube (120), which is connected to the rear end of said connector body (110), and a gas conduction tube ( 124), which is disposed within and interacts with said arm support tube (120) to define between them a small annular cooling space (126) to channel gas from the shaft (20) to the free end of the revolving arm (26), and the inner section of said gas conduction tube (124) forms a retaining channel o (128) for refrigerant, - said supply and return means include at least one refrigerant supply channel (140) disposed in said solid connector body (110) around said bore (132), wherein that at said rear end of said solid connector body (110) at least one fluid supply channel (146, 146 ') is in communication with said small annular cooling space (126) and at least one of said return channel (140) is in communication with said return channel (128), and said bore (132), into which said securing screw (150) is rotatably engaged, extends axially through said solid connector body ( 110), and by said abutment surface, on which said threaded bushing (160) rests, is formed at the free end of said solid connector body. A plug according to claim 1, characterized in that said securing means further comprises a positioning tube (172) attached to a first end of said securing screw (150) and extending through the entire revolving arm (26). to the free end of it. A plug according to claim 1, characterized in that said securing means further comprises a drive tube (170) fixed at a first end to said threaded bushing (160) and extending through the entire revolving arm (26). to the free end thereof, with its second end supporting a coupling head (174) for coupling thereto a drive key to transmit torque to the threaded bushing (160) through said drive tube (170). A plug according to claim 3, characterized in that said securing means further comprises a positioning tube (172) attached at a first end to said securing screw (150) and extending through the entire revolving arm (26). to the free end thereof, said positioning tube (172) being coaxial and rotatably supported within said drive tube (170). A plug according to claim 3 or 4, characterized in that: one end of said arm support tube (120) is connected to said solid connector body (110) and the other end is closed by an end cap (180). , and said drive tube (170) extends axially through said gas conduction tube (124) and its free end is rotatably supported in a hole in said end cap (180). A compound according to any one of claims 1 to 5, characterized in that: - said connector body (110) is a solid molded body, and said bore (132), in which a cylindrical body portion (152) is rotatably embedded, at least one of said coolant supply channel (146) and at least one of said coolant return channel (140) are provided as holes in said solid molded body. A compound according to any one of claims 1 to 6, characterized in that said compartment (100) has a first concave conical seating surface (112) located in proximity to its lower surface (144) and a concave cylindrical orienting surface. (116) located closest to the inlet opening of said housing (100), said connector body (110) has a first convex conical backseat surface (112 ') and a convex cylindrical guiding surface (116'), interacting respectively with said concave conical seating surface (112), and with said concave cylindrical orienting surface (116) in said housing (100). A compound according to claim 7, characterized in that: - said housing (100) has a second concave conical seating surface (114) therein, said concave cylindrical guiding surface (116) resting between said seating surface concave conical seat (112) and said second concave conical seating surface (114), and said connector body having thereon a second convex conical backrest surface (114 '), said convex cylindrical guiding surface (116' ) resting between said first convex tapered backing surface (112 ') and said second convex tapered backing surface (114'). A compound according to claim 8, characterized in that all said conical surfaces (112, 114, 112 ', 114') are annular surfaces of a single cone. A plug according to claim 9, characterized in that said cone has a tapered angle within the range of 10 to 30 °, preferably within the range of 18 ° to 22 °. A compound according to claim 8, 9 or 10, characterized in that at least one refrigerant gas channel is disposed in said revolving arm fixing joint (28) having an opening in said concave cylindrical guiding surface (116). ), and at least one refrigerant gas channel is disposed in said connector body (110) of said revolving arm (26) which has an opening in said convex cylindrical guiding surface (116 '), said openings overlapping when said connector body (110) is seated on its seats in said housing (100). A rod according to any one of claims 1 to 11, characterized in that said revolving arm fastening joint (28) comprises a ring-shaped body made of refractory steel, said compartments (100) being arranged radially in said body. molded into ring shape. A compound according to claim 12, characterized in that said axle (20) includes a support structure consisting of said revolving arm fastening joints (28) and intermediate support tubes (68) which are interposed as support members. loading of structural load between said revolving arm fixing joints (28). A plug according to claim 13, characterized in that said revolving arm fixing joints (28) and said intermediate support tubes (68) are welded together. A furnace according to any one of claims 1 to 14, characterized in that at least one section of said shaft (20) extending between two adjacent crucible chambers (12) comprises: an intermediate support tube (68) fixed between two arm clamping joints (28) to form an outer wrap, an intermediate gas conduction wall (72) disposed within said intermediate support tube (68) to delimit an annular main refrigerant gas supply channel (52 ) between them, and an internal gas conduction wall (74) disposed within said intermediate support tube (68) so as to delimit an annular main refrigerant gas distribution channel (54) between them, said conduction wall (74) further defining the outer wall of a central outlet channel (56). A rod according to claim 15, characterized in that said arm clamping joint (28) comprises a ring-shaped body comprising: at least one of said compartments (100) for engaging said connector body (110). ) of said revolving arm (26), a central passage (90) forming said central discharge channel (56) for refrigerant gas within said arm clamping joint (28), - a first group of secondary passages ( 92) disposed in a first annular section (94) of said molded body, so as to provide passageways for the refrigerant gas flowing through said annular main refrigerant gas distribution channel (54), a second group of secondary passages (96). ) arranged on a second ring section (98) of said molded body to provide gas passages s refrigerant flowing through said annular main refrigerant gas supply channel (52), a first conduit means disposed in said molded body so as to interconnect said annular main refrigerant gas supply channel (52) with an opening outlet (102 ”) within at least one compartment (100), and a second channeling means disposed in said molded body, so as to interconnect a gas inlet port (102 ') within at least one compartment (100) to said central passageway (90). A pipe according to claim 16, characterized in that said second channeling means comprises an axially extending perforation (104) of said housing (100). A pipe according to claim 16 or 17, characterized in that said first channeling means comprises at least one oblique hole (102) extending through said ring-shaped body from the second ring section (98). into a lateral surface delimiting said compartment (100). A pipe according to claim 16 or 17, characterized in that: said arm support tube (120) is a thick-walled stainless steel tube that extends the full length of the revolving arm (26) and is welded at one end to a protruding surface (122) on the rear side of the connector body (110). A compound according to any one of claims 1 to 19, characterized in that said revolving arm (26) further comprises: a micro-porous thermal insulating layer (194) disposed on said arm support tube (120), and a metal protective cover (186) covering said layer of microporous thermal insulator (194). A compound according to claim 20, characterized in that said revolving arm (26) further comprises: metallic revolving teeth (30) fixed to said metal protective cover (186) by welding, and anti-rotating means (196) disposed between the said arm support tube (120) and said metal protective cover (186).